1. Field of the Invention
The present invention relates to an ink cartridge that contains ink, and a printing system.
2. Description of the Related Art
Ink cartridges that are generally known comprise an ink bag that contains ink in its interior, a plug for extracting the contained ink from the ink bag, and a rectangular parallelepiped-shaped plastic case configured to house the ink bag.
The ink cartridge of the above-described prior art reference is provided with an opening on the housing. A needle that pierces into the rubber stopper of the plug and introduces the ink within the reservoir portion passes through the opening. While the plug can be visually checked from this opening, visually checking the volume of ink within the reservoir portion is difficult.